Crystal System: Orthorhombic
Status of Occurrence: Confirmed Occurrence
Distribution: Rare
Chemical Composition: Copper sulphate hydroxide
Chemical Formula: Cu3(SO4)(OH)4
Method(s) of Verification: XRD - University College of North Wales, Bangor.

Chemical Group:

  • Sulphates

Geological Context:

  • Supergene: post-mining oxidation & weathering deposits
Introduction: antlerite is a supergene copper mineral that tends to be restricted in occurrence to arid, highly acidic environments. Associated minerals are gypsum, other copper sulphates such as brochantite and chlorides such as atacamite.
Occurrence in Wales: the physical and chemical conditions under which antlerite forms are uncommon in the UK and there are only a handful of localities, of which the only Welsh one is Parys Mountain. Here, oxidation of chalcopyrite in very low pH conditions (due to super-abundant gangue pyrite) has created the required environment.

Key Localities:

  • Parys Mountain, Anglesey: antlerite occurs as a post-mining mineral in underground chambers. It forms brilliant green powdery masses in association with brochantite. Crystals are only visible under the scanning electron microscope (Jenkins et al., 2000).


  1. Jenkins, D. A., Johnson, D. B. & Freeman, C., 2000. Mynydd Parys Cu-Pb-Zn mines: mineralogy, microbiology and acid mine drainage. pp. 161-179. In: Environmental Mineralogy: Microbial Interactions, Anthropogenic Influences, Contaminated Land and Waste Management (Cotter-Howells, J. D., Campbell, L. S., Valasami-Jones, E. & Batchelder, M., eds.). The Mineralogical Society of Great Britain & Ireland, London.